Safety scaffold winch



I July 29, 1947.

' J. M. BENSON SAFETY SCAFFOLD WINCH 2 SheefiS Sheet 1 Filed May 20, 1946 mam JuEy 29, 1947. J. M. BENSON 2,424,910

SAFETY SCAFFOLD WINCH Filed May 20, 1946 2 Sheets-Sheet 2 JMBenson I Patented July 29, 1947 Jesse M; Benson, Concord; Tenn, assignor to SasgenDerrickCo Chicago, 111;, a corporation.

of Illinois Application May-20, 1946, Serial No. 670,945

l'Claim: 1

This invention relates to safety, scaffold;

An object of this invention is to provide an improved scaffold structure including a safety winch therefor.

Another object of this invention is to.v provide an improved scaffold winch embodying multiple safety means so that the winch will not be ac.- cidentally lowered by any excessive weight or sudden jar on either the scaffold or the winch.

A further object of this invention is to-provide in a winch of this character atorque operated locking means for locking thewinding drum against unwinding, the locking means being releasable when the winding crank is turnedin-a winding direction.

A further object of this invention is to-provide a scaffold winch which is so constructed that the winding crank will serve as a brake in the unwinding of the drum, as in the unwinding operation it is necessary to reverse the rotation of the crank and the latter releases the locking means in proportion to the reverse rotation.

With the foregoing and other objects in view as may hereinafter more fully appear, the invention consists of the novel construction, combination and arrangement of parts as willbe more specifically referred to and'as illustratedin the accompanying drawings wherein is shown. an embodiment of the invention, but it is to be-understoodthat changes, variations and modifications may be resorted to without departing from the spirit and scope of the invention.

In the drawings, wherein similar reference characters designate similar parts throughout the respective views,

Figure 1 is a detail side elevation of a scaffold and winch structure constructed according to an embodiment of this invention,

Figure 2 is a fragmentary sectional view taken on the line 2-2 of Figure 1,

Figure 3 is an enlarged sectional view taken on the line 3-3 of Figure 2,

Figure 4 is a fragmentary sectional view taken on the line 4-4 of Figure 3,

Figure 5 is a fragmentary plan view of the driving gear and shaft therefor.

Referring to the drawing, the numeral ll! designates generally a winch structure which has secured to the lower end thereof a scaffold or platform supporting member, generally designated as II. The scaffold or platform supporting member ll comprises a pair of downwardly divergent bars I 2, which are formed with vertical upper end portions l3, and with vertical lower portions I4. A horizontal connecting bar I5 connectsthe extensions [4 together and a platform iii-is: adapted'to engage on the horizontal bar it. A-rail supportingbracket I! is secured to one of the-bars I2 andincludes a base plate is secured by fastening members it to the bar I2. An upwardlyand outwardly extending arm 20 is carriedby the base l8,- and has formed integral with the upper outer'endthereof, a rectangular loop or eye'2 l within which a guard rail 22 is adapted to engage.

The vertical extensions l3 are disposed between the spacer plate 23- having enlarged tubular bosses 24-at the upper and lower portions thereof through which-la pair of. fastening members 25 engage for securing the platform supporting structure H to the frame of thewinch H). The winch lfi'includes a pair of frame members 26 and 27 which are disposed inspaced apart relationbeing' held in spaced apart relation by means of the spacer 23'and an upper tubular spacer Z8 engaging about a bolt 29which extends'through the plates 26 and'2l.

A winding drum 3c is rotatably mountedon a shaft 3! journaled through bearings 32 and 33 carried by the plates 26 and 27- respectively. The winding: drum 3% includes a spur gear 34 at one endthereof Which is adapted to mesh with a pinion-.35. The pinion 35 is carried by a winding shaft. 3%: disposed" above the drum 30- and journaled inbearings 3"!- and 38 carried by the plates 26 and 21. The'shaft 36 is formed with a threaded part 39 on whichthegeartdthreadably engages, andablock lflris-fixed on shaft 36 and is formed with a cutout 4i confronting the gear 35 which has certain of the teeth 35a projecting into the cutout so that the gear 35a will be limited in its rotation and movement to the left on shaft 36. In this manner gear 35, when moved to a position disengaging clutch 43 from ratchet clutch 44 will not be frictionally locked. The length of the cutout 4| is such as to provide sufficient movement of gear 35 on shaft 36 to declutch ratchet 44,

A plate 42 is fixed to shaft 36 and comprises one portion of a braking element and another braking plate or element 43 is fixed to or formed integral with gear 35. A toothed plate 44 is rotatably mounted on shaft 36, at one end of the threads 39, and is interposed between the plates 42 and 43. A pawl 45 is rockably mounted on bolt 29 and is adapted to engage the teeth 46 of plate 44 so as to hold plate 44 against rotation in one direction. A second dog or pawl 41 is rockably mounted on bolt 29 and is adapted to engage the cured thereto a winding crank 48 which includes a lever 49 and a right angularly disposed handle 50. The lever 49 is rockably mounted on a pivot 5| engaging through the adjacent end of shaft 36. Handle 50 constitutes a second safety means, which, as shown in Figure 1, is adapted in one position thereof, to enga e against the adjacent edge of plate 21.

In the winding position of crank 48 this crank is swung upwardly and outwardly through an arc of substantially 180 to the position shown in Figure 3 so that handle 50 will be in outwardly extending position.

In the use and operation of this winch the cable C is wound on drum 30, crank 48 being swung outwardly as shown in Figure 3. As crank 48 is turned'in a clockwise direction, as viewed in Figure 2, drum 30 will rotate in a counter-clockwise direction. Rotation of shaft 36 in a clockwise direction will cause thread 39 to draw plate 43 tight against ratchet plate 44. Ratchet plate 44 will be tightly held between plates 42 and 43 so that these three plates will rotate clockwise as a unit with pawl 45 riding over the teeth 46. As drum 30 is rotated dog 47 will also ride over the teeth of gear 34 so as to prevent reverse rotation of drum 30. In the event crank handle 48 should be dropped, or the hand gripping this crank handle should become disengaged therefrom, the torque of drum 38 will cause gear 35 to rotate in a counter-clockwise direction which direction will be to effect binding of the two plates 42 and 43 on ratchet plate 44.

As ratchet plate 44 is always engaged by dog 45, the reverse torque on gear 35 will cause this gear to be stopped in its rotation so that drum 30 will thereby be held against turning to unwind the cable C therefrom.

In the event it is desired to effect an unwinding of cable C from the drum, crank 48 is rotated slowly in a counterclockwise direction so as to disengage the plate 43 of gear 35 from ratchet plate 44. The speed of unwinding can readily be controlled by the desired reverse rotation of crank 48 and if further unwinding is undesired it is only necessary to stop rotation of crank 48 and shaft 36 whereupon gear 34 will turn gear 35 to effect a binding of the two plates 42 and 43 on opposite sides of ratchet plate 44.

As an added safety factor crank 48 may be swung downwardly to dispose the handle 50 in an inwardly projecting position which is the position shown in Figure 1, and .this handle may then be engaged with one edge of plate 21. In this manner the frame of the winch will coact with the braking means hereinbefore described to positively lock the winding drum against rotation in an unwinding direction.

I claim:

A winch comprising a frame structure, a winding drum rotatable in said frame structure, a gear fixed relative to said drum, a drive shaft journaled in said frame structure, a brake comprising a clutch operating thread on said drive shaft, a

driving pinion operatively connected with said clutch thread, a clutch plate fixed relative to said pinion, a second clutch plate fixedly carried by said shaft, an intermediate clutch plate loose on said shaft between said first and second clutch plates, a dog rockably engageable with said intermediate clutch plate for holding the latter against rotation in the unwinding direction 01 said drum, a pivot disposed transversely of said shaft adjacent one end thereof, a crank comprising an arm and a handle normal to said arm pivotally mounted on said pivot, said handle in the operative position of said crank extending away from said frame, said crank when rotated on said pivot through an arc of substantially degrees having the handle disposed in inwardly projecting position with respect to said frame whereby said handle will lock said shaft against rotation in an unwinding direction of movement of said drum on failure of said brake, and correlated stop means fixed relative to said drive shaft for limiting relative rotation between said pinion and drive shaft.

' JESSE M. BENSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number 

